The present invention relates to improvements in and relating to air bag restraint systems.
In air bag restraint systems, the air bags are located behind covers formed in trim panels, so that upon inflation of the air bag, the bag will burst through the cover and be deployed in front of the occupant of the vehicle.
It is desirable that upon inflation of the air bag, the parts of the burst cover will remain attached to the trim panel, so that they will not fly off and cause possible injury to the occupants of the vehicle. Furthermore, it is important that the burst parts of the cover do not intrude significantly into the passenger compartment as this again may present a hazard to the occupants, during a collision.
Hitherto, it has been proposed to form the cover from a pair of horizontally hinged doors, one door hinged along its upper edge and the other along its lower edge, a frangible seam being provided between the two doors which upon inflation of the bag will fracture to permit the doors to open by pivoting along their hinges. According to one form of construction proposed, an aluminium pressing defines the frangible seam and hinge formations for the doors, suitable facia panels being applied to the aluminium pressing. However, due to the necessarily weakened nature of the frangible seam and hinge formations, the aluminium pressing forms a frail construction and requires supporting jigs during application of the trim facia and installation into the vehicle.
Furthermore, the formation of the cover from a pair of doors requires a trim finisher to cover the central seam which places restraints upon the final appearance of the facia.